A conventional hot coiler drum applied in a steckel mill is usually processed by casting integrally. The conventional hot coiler drum usually only has a lifespan of 4 to 6 months because the conventional hot coiler drum rolls steel at 900-1200° C. It is also difficult to repair a defective conventional hot coiler drum since the conventional hot coiler drum is formed by integrally casting. Besides, the conventional hot coiler drum, formed by once integrally casting, has a diameter of 1.3 to 1.9 meters and a length of 3 to 5 meters, without a guarantee that all the used heat-resistant steel is processed by a solid solution, which affects the lifespan thereof. Moreover, there is no large-sized casting device in China and thus the conventional hot coiler drum mainly depends on import.